Topic: i've got a wierd problem

[braves3331]

today i took the jeep on a test run up in the hills for about an hour, and she ran pretty good. i got it back, parked it in the driveway, turned it off, went to sweep out the garage for like 5 minutes, went back to the jeep to start it up and pull it in the garage, and she wouldn't fire. she would crank, but not fire.

i could hear the fuel pump turning on with no problem. i looked inside the throttle body, and a light smoke was coming from it. poured a dab of gas in it, and the smoke got a little heavier for a couple seconds...but still would not fire. so i pushed it in the garage, tried again, and nothing, so i let it sit.

4 hours later, i go out in the garage and see if she'll fire, and first try, she starts right up...

any ideas on what the problem might be? this is the first time this has ever happened to the jeep.

lately, the injector has been making noise, and i have plans to change it. but would a bad injector cause a problem like this? should i change the strainer on the fuel pump? one of the sensors maybe? any help is appreciated. thank you

[JBFried67]

I'm not real knowledgable on the pre 93' engines.   On my 93' I had this problem and it turned out to be the CPS.

[oakesmi2]

Well let’s think about this.

Engine needs 4 things to run
1. Air
2. Fuel
3. Compression
4. Spark

1. Air I would assume that it was cranking and air was getting in the Cylinders.
2. Fuel - you put gas down the throttle and no fire
3. Compression, would assume that you did not have a sudden drop in Compression
4. Spark - well this would be my thought on this one. I would trouble shot the ignition. Possibly the coils, but I don't know.  That is where I would look.

[87AMC_YJ]

I've had a very similiar experience with my '87 YJ.  I've changed the fuel pump, coil, had the TBI injector cleaned, changed a couple of temp sensors, MAP, and did a tune up as well.  It has gotten better, but still at times suffers the same symptoms.  Next is a replacement of the TBI's fuel pressure regulator and the ECM (I think that is the correct term).  
I'd be interested to know if you were able correct yours since you first posted the problem.

[Jeffy]

My guess would be the CPS also. (Although I'm more used to workon on MPFI's.) It may have been fouled from your adventures and cleared/dried after it sat.

[87AMC_YJ]

El Jefe,
         Thanks for the input.  It'll be a couple of months before I can do any further troubleshooting, etc as I am currently on deployment in the Persian Gulf.   This and other sites help me get me "to do" list ready to go for when I get home.  I'll let you know how it works out.  Again, thanks.

[sharpxmen]

was the smoke maybe gas vapors?  Then might be an injector leaking and then it won't start due to too much gas - that might explain why it started after sitting 4 hours.